A problem often encountered in the polymer film art relates to the difficulty of providing strong adhesion between substrates and functional coatings applied to them. This is particularly so in the case of polyester-based substrates. To deal with the problem, a primer layer or coating is generally applied to the polyester substrate to improve adhesion between the substrate and the functional coating. A particularly difficult adhesion problem is often encountered in the manufacture of optical films having a microstructured surface layer disposed on a multilayer optical film. The microstructured surface layer is formed by coating a UV-curable acrylic resin on the multilayer optical film followed by curing the resin against a microstructured roll.